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A Republican primary season marked by a blistering campaign spending spree and less-is-more approach to government comes to an end Tuesday with two wealthy businesswomen poised to make history for the GOP.

Former eBay chief executive Meg Whitman and former Hewlett-Packard CEO Carly Fiorina have become the front-runners to lead the Republican Party this fall. If the most recent polls hold, it would be the first time the party would have put a woman -- much less two -- at the top of its ticket in the nation's most populous state.

Whitman has built a wide lead over her rival for the Republican nomination for governor, state Insurance Commissioner Steve Poizner, thanks in large part to spending from her personal fortune. The billionaire has spent $81 million so far, all but about $10 million of it from her own bank account.

Fiorina has had a come-from-behind story in her race for the GOP nomination for U.S. Senate, greatly outspending her two challengers. She also has appealed to conservative voters with her views on abortion, guns and gay marriage but will face a difficult task trying to unseat incumbent Democratic Sen. Barbara Boxer if she emerges victorious in Tuesday's primary.

She holds double-digit leads against former congressman Tom Campbell and state Assemblyman Chuck DeVore.

Republicans hope the anti-incumbent mood that has swept the nation will help them defeat Boxer and state Attorney General Jerry Brown, two of California's most well-known Democrats. Brown is seeking a comeback as governor, a post he held from 1975-83 in the era before term limits.

Brown and Poizner have public events scheduled early on Election Day, while Whitman has no planned public appearances, an unusual move for a top-tier candidate. Whitman's campaign said she will avoid the typical Election Day photo-op because she already has cast her mail-in ballot.

Whitman has been criticized for her poor voting record and has acknowledged that she did not vote for most of her life. She had been expected to vote near her home in Atherton, south of San Francisco. Her spokesman, Tucker Bounds, said Whitman decided to vote absentee for convenience because she will be in Los Angeles on Tuesday.

Turnout for the primary is expected to be relatively light, with perhaps a third of registered voters casting ballots. Of the 16.9 million Californians registered, 40 percent -- or 6.8 million -- requested vote-by-mail ballots. As of Monday, 1.8 million of those ballots had been returned.

Interest is expected to be higher among Republicans because of the gubernatorial and Senate contests. Brown and Boxer did not face serious challengers.

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